It is perfectly reasonable after the solve by Donald Gene and Bettye June Harden in the August of 1969, to believe that all the remaining ciphers contain a message, after all, what would be the point of them other than a joke on Zodiac's part. It is my contention that the remaining three ciphers may have been linked by religion (and Jesus Christ in particular).
The Zodiac chose a Celtic Cross style moniker, talked of "paradice" and the "afterlife," and placed crucifix style designs in his Halloween and 13-Hole postcards. You could say the Zodiac Code was the forerunner to the Da Vinci Code.
The key to the Zodiac Code is the previously discussed 13-Symbol cipher, where the Zodiac splits the alphabet A through M to expose perfect symmetry in the third cipher. This is the template we shall use in the 13-Symbol and 32-Symbol ciphers, and in both instances arrive at exactly the same holy number. The Zodiac crosshairs can be noted in every cipher or code, so it is imperative we derive a mathematical figure for this moniker. But first we shall present the Zodiac Code that will be used on both ciphers.
The Zodiac used what appeared to be an upside-down Aries symbol on the April 20th 1970 13-Symbol cipher. Many people also considered that the three circled 8's were in fact three circled Taurus symbols. But the reason the Zodiac Killer circled them, was possibly so they could be interpreted as both. Since we are dealing with the Zodiac horoscope, we will take the characters as one Aries and three Taurus symbols.
This generates the figure 315 for the Zodiac crosshairs.
Because we will be using Aries and Taurus in the 13-Symbol cipher, I will explain how to arrive at the figures in brackets:
ARIES = A+R+I+E+S = 1+5+5+5+6 = 22.
TAURUS = T+A+U+R+U+S = 7+1+6+5+6+6 =31.
ARIES =22, TAURUS = 31.
Before we move on it is important to mention the following again.
In Christian numerology, the number 888 represents Jesus, or sometimes more specifically Christ the Redeemer. This representation may be justified either through gematria, by counting the letter values of the Greek transliteration of Jesus' name, or as an opposing value to 666, the number of the beast. Wikipedia. In English gematria the figure for Jesus is 444.
If the Zodiac was creating his own bible code and referencing the rebirth of Christ using the number 8 for infinity, one would hope to find the figure 444 in the 13-Symbol cipher shown below.
Let us proceed and place the numbers alongside the relevant characters (see below).
Notice again how the alphabetical characters only produce the figures 3, 1 and 5, as does the figure 315 representing the Zodiac crosshairs. The total value of the 13-Symbol cipher is 444, representing Jesus.
Below I have used the same technique, using the Zodiac Code, representing the letters of the 32-Symbor cipher by numbers. The Zodiac crosshairs are again attributed the 315 value and the Aries symbol the figure 22 once more. This time however, we have an Omega symbol, so we have to attribute it a figure. OMEGA = O+M+E+G+A = 2+1+5+7+1 = 16. The six geometric shapes in the 32-Symbol cipher cannot be attributed a name, and therefore cannot be attributed a value. They have been marked with a red X. You can see below, that when the numerical values are added up we arrive at the figure 444 once again. Zodiac representing the figure 888, and both the remaining ciphers totaling 888. Whether it be 444 or 888, the reference to Jesus or Jesus Christ through the bible code of the Zodiac Killer is certainly possible.